Actually, let me back up… The episode began with the moment both Kara and Mon-El have been dreading: It was time for the Legion to return to the future. How do I know they’ve been dreading it? Well, besides the fact that neither one of them has a poker face, they had this transparent exchange at the top of the hour:

Kara: It’s no secret that I struggled when you got here.Mon-El: You weren’t the only one.Kara: But I can honestly say now, truthfully, I’m really happy i got to see you again [and] witness the man you’ve become.Mon-El: It meant the world to me to be back here with you … to fight by your side.Kara: I’m really going to miss you.

Unfortunately, their big dramatic goodbye was cut short by news of an attack: While hunting Ruby, Reign crash landed in Lena’s apartment, interrupting another sexy conversation, this time between the boss lady and her boy toy James. (Man, Reign really has terrible timing.) Thanks to Lena’s quick thinking — and her at-the-ready can of Kryptonite spray, apparently — Reign flew off empty handed. Little did she know that Ruby was safely stowed away in Lex’s (invisible?) mansion.

From there, Kara and J’onn went to protect Sam’s mom Patricia, who filled in a few blanks in her daughter’s backstory: Sam began exhibiting curious signs when she turned 10, but rather than helping her through those struggles, Patricia punished her, eventually kicking her out of the house completely. So she refused to be taken to safety, instead choosing to stay behind and finally face the daughter she failed years ago. Kara and J’onn allowed her to stay against their better judgment, but she didn’t last long once Reign showed up and got all stabby. (R.I.P., Mama Reign!)

Back in National City, James encouraged Lena to offer Supergirl some of her synthetic Kryptonite, going so far as to say the Girl of Steel would be “grateful” for it. (She wasn’t.) But it certainly came in handy when Reign attacked Alex and Ruby at Lex’s mansion; Kara distracted Reign with talk of her “code” (don’t hurt the innocents!) long enough for Mon-El to load a gun with Kryptonite and take her out.

Oh, right, Mon-El. He and Imra — aka the most understanding woman in this or any other time — had a long-overdue heart-to-heart on their way back to their own time:

Imra: I risked our lives and our marriage to stop Pestilence. I still believe it was worth it. I hoped that once we left, you’d put your feelings for Kara behind you. Yo tried to bury your feelings, you behaved honorably.Mon-El: I would never do anything to dishonor you.Imra: I know, but I need a partner who will choose me with a full heart. Go back. Help her fight Reign. If you stay, that’s your destiny. If you return, I’ll know you have no doubts.

(Again, wow. She’s being a lot cooler about this than I would if I was Mon-El’s wife.)

But the most surprising confrontation was saved for the end of the episode when Kara got an earful from Lena. Not only does Kara now know that James never even looked in Lena’s vault, but she also knows how Lena feels about the Girl of Steel: “I can never trust her again.” Um, yikes?

Also worth discussing…

* Remember when Brainy and Winn almost made out? I do!

* Maybe this is a dumb question, but how old is Ruby? Is she going to start exhibiting abilities soon?

* M’yrrn’s love of “brown water” will never get old, even if his story is getting more heartbreaking every week.